Disposable container for a centrifuge

ABSTRACT

A blood component separating device comprises a centrifuge bowl adapted for rotation about its axis in a centrifuge. The bowl defines an outer circumferential wall plus an inner circumferential wall, spaced from the outer wall, to define a circumferential slot adapted for receiving blood components. Access tubing is adapted for communication with the slot. Preferably, an elongated, flexible, collapsible inner liner is provided in the slot. Individual access tubing also may communicate with an elongated container interior between the ends of the elongated, collapsible container. Furthermore, a portion of the slot may define the shape of an outwardly extending spiral, to provide an increasing gravitational field upon fluids therein as the fluid moves along the slot.

This application is a division of U.S. application Ser. No. 824,182,filed Aug. 12, 1977, now U.S. Pat. No. 4,934,995.

BACKGROUND OF THE INVENTION

Blood components are separated from units of human blood and utilizedfor separate therapy in patients. For example, blood plasma may beadministered without red cells. Also, the packed red cells can beadministered to a patient with a minimum of plasma or other suspendingsolution. Furthermore, platelets or white cells may be administered asspecific components. Also, platelet-poor plasma is another product fromblood utilized in various forms of therapy.

The invention of this application relates to a centrifuge which can beused to obtain, for example, separate portions of platelets, plasma(including platelet-poor plasma), other white cells, and packed redcells, The device of this invention can operate to process, in acontinuous operation, an unlimited amount of blood from a donor,processing the blood to separate and return the red cells to the donor,and to harvest, as desired, the white cells, platelets and plasma. Thecentrifuge bowl or container of this invention utilizes a radially thin,circumferential flow path for the blood and plasma being processed, toprovide a long, thin circumferential flow path in which a continuousprocess of separation may take place. As a result of this, a sweepingaction may take place over the thin, sedimented layer of the slightlyheavier particles such as the blood cells, to move the slightly lighterparticles (for example the white cells) downstream with respect to thered cells. This permits the use of sharply lowered G forces than iscustomarily used in conventional blood separation, with the slightlylighter cells being urged to move downstream more quickly than theslightly heavier red cells, to provide a more efficient cell separation.

Also, the thin, circumferential operating path provides a very shortsedimentation distance, no more than the restricted width of the path.This also provides the advantage that the centrifuge bowl container ofthis invention has a low blood volume so that a relatively small amountof blood is removed from the donor at any one time while at the sametime facilitating the sedimenting of red cells and protecting theplatelets from the known, undesirable effects of high G forces in excessof one thousand Gs.

Furthermore, the device of this invention permits the accumulation ofwhite cells and platelets during continuous operation, in which the redcells are sedimented along the circumferential path and then withdrawnfor reinfusion to the patient on a continuous or repeating basis. At thesame time, the white cells and/or platelets, which generally compriseless than one percent of the blood volume, can be accumulated during theoperation so that large amounts of white cells and platelets can beharvested in the single operation.

The above objections are accomplished in the apparatus of this inventionwith minimal shear stresses being placed on especially the white cellsand platelets.

The invention of this application effectively provides an efficient,sterile means for obtaining blood components from a donor or fromreservoirs on a semi-automated basis, utilizing a disposable containerof novel configuration.

DESCRIPTION OF THE INVENTION

In accordance with this invention, a blood conponent separating devicecomprises a centrifuge bowl or chamber adapted for rotation about itsaxis in a centrifuge. The bowl defines an outer circumferential wall,and an inner circumferential wall spaced to define an annularcircumferential slot, adapted for receiving blood components. The slotis adapted to contain access tubing, and aperture means in the bowlpermit the access tubing to pass out of the slot for connection with anexterior member.

In accordance with this invention, a portion of the slot adjacent theaperture means defines the shape of an outwardly extending spiral. Theeffect of this is to provide an increasing gravitational field uponfluid therein as the fluid moves along the slot. This causes heavierparticles such as blood cells to settle outwardly, and then to slide tothe outward spiral end portion of the slot for collection. At the end ofthe spiral portion of the slot, a radially inwardly extending stepportion of the slot may be provided, whereby red blood cells positionedin the slot during centrifugation may collect at the outer end of thespiral portion.

Pockets can be provided in the outer circumferential wall defining theslot, for collection of blood cells with access tubing communicatingwith said pocket.

Also, a portion of the slot, positioned beyond the inwardly extendingportion from the spiral portion, may define a generally circular portionwhich is preferably positioned radially inwardly from the spiralportion, for the purpose of collecting platelets at a lower level ofcentrifugal force than the red cell collection portion

A flexible, elongated, flat container or bag for blood components may bepositioned in the circumferential slot with the access tubing being incommunication with the container interior. The access tubing may bepositioned adjacent each end of the elongated, flat container forpassage of blood components through the slot within the container. Also,additional access tubing may communicate with the elongated, flatcontainer between the ends thereof for collection of centrifuged heaviercomponents such as red and white blood cells.

In one embodiment, the container bowl of this invention may processblood plasma to remove platelets which, upon centrifugation, collect onthe outer wall. Alternatively, the bowl of this invention may be used toprocess whole blood to collect both red and white blood cells andplatelets, with platelet-poor plasma passing out of the end of the bagpositioned within the circumferential slot. The bowl may also be used tocollect red blood cells alone.

Blood, plasma, or other liquid may be fed to one end of the elongated,flat bag for passage through the bag during centrifugation. Thecentrifuged liquid is then withdrawn from the other end of the bag,while red and white cells may be removed at various points intermediatealong the container as illustrated herein.

The tubing which is connected to the spinning, elongated, flat bag maybe connected to a stationary liquid source and a receptacle forprocessed liquid outside of the centrifuge by the use of a conventionalstructure making use of the principles of Adams U.S. Pat. No. 3,586,413,Khoja, et al. U.S. Pat. No. 3,986,442, and similar prior art utilizingthe feature of preventing the communication tubing from being twisted bymeans of the precise rotational relationship described in those patents.Accordingly, a conventional centrifuge can be adapted to receive thebowl of this invention, utilizing the rotational principles for thecommunication tubing described in the above-cited patents, in which oneset of ends of the communication tubing is spinning with the centrifugebowl and the other ends of the tubing are stationary, and connectedoutside of the centrifuge to a liquid source and a receptacle forprocessed liquids.

Referring to the drawings, FIG. 1 is a top plan view of an embodiment ofthe centrifuge bowl of this invention for the collection of both redcells and platelets.

FIG. 2 is a sectional view of the centrifuge bowl of this invention,taken along line 2--2 of FIG. 1.

FIG. 3 is an elevational view of a flexible, elongated, flat containerwhich may be utilized herein.

FIG. 4 is an enlarged, fragmentary elevational view of the container ofFIG. 3.

FIG. 5 is a detailed perspective view of an alternate technique forconnecting the tubing to the container, with portions broken away.

FIG. 6 is a longitudinal sectional view of the connection illustrated inFIG. 5.

FIG. 7 is a plan view of an alternate embodiment for the centrifuge bowlof this application.

FIG. 8 is a perspective view of a third embodiment of the centrifugebowl of this application, with one portion shown schematically.

Referring to FIGS. 1 and 2, centrifuge bowl or container 10 isillustrated, comprising a bowl member 12 and a cover 14 which isremovable from the bowl member, to define an annular channel or slot 16between cover 14 and bowl 10 as shown in FIG. 2. Typically, channel 16may be 50 mm. high, tapering from about 3.5 to 4.5 mm. (preferably 4mm.) in width at point 17 to about 12 mm. in width at point 19, and thennarrowing again. Overall, channel 16 may be about 28 inches incircumference.

Bowl assembly 12 defines a central aperture-defining sleeve 18, topermit attachment of the bowl to a centrifuge rotor for spinning of thebowl 10.

Referring to FIG. 3, a flexible, elongated flat container or bag 20 forplacing in annular chamber 16 is disclosed. Container or bag 20 may bemade out of a single piece of plastic, folded into U-shaped crosssection at the bottom, and sealed with R.F. (Radio Frequency) seals 22at the ends thereof, or by any other desired sealing technique. Also, anupper R.F. seal 24 is provided to seal an interior portion 26 of thecontainer in sterile manner from the exterior.

Tubings 28, 30 are provided at each end of the flexible, flat containeror bag to serve as an inlet and an outlet, tubing 28 being typicallyused as the inlet and 30 as the outlet. Heat seal 24 may slope upwardlyas shown for the purpose of encouraging the downstream migration of airbubbles.

In the unsealed portion of bag 20, a plurality of perforations 32 areprovided to fit around pins 34, which project from the annular wall 35of bowl 12 inwardly to serve as a hanger means for bag or elongatedcontainer 20 when it occupies annular aperture 16.

Bag 20 also defines intermediate connection ports 36, 37 which arepositioned to communicate with sealed chamber portion 26 of theelongated bag or container. Ports 28, 30, and 37 penetrate the seal 24in conventional, sealed manner.

Seal 39 defines a constricted portion inside of the interior of bag 26to divide it into two segments separated by narrow communicating channel41 as shown in FIG. 3. This permits, after use, the easy sealing andseparation of the bag at constricted channel 41 for harvesting ofplatelets in one segment thereof.

A detailed connection system for communication tubing 36 in theelongated bag or container 20 is shown in FIGS. 5 and 6. There, afragment of elongated, flat container 20 is shown. Container 20 may bemade of thin-walled, tubular plastic material, for examplepolyvinylchloride, among other materials. An aperture 38 is cut in theside wall of bag 20a, and is covered by a filter screen 40. The tubing,for example communication tubing 36, (a portion of which is separatelyshown for clarity in FIG. 5) defines a plurality of perforations 42 inthe side. The ends of tube 36 loop together to form in each case asingle connecting tube 44.

Outer wall 46 tightly and sealingly surrounds a portion of tubing 36which may be R.F. sealed to the wall of tubing 20. In particular, a sealline 48 runs around aperture 38 between outer wall 46, and tube 36 andthe wall of bag 20, to provide a seal around aperture 38.

As shown in FIGS. 1 and 2, bag 20 is positioned in annular slot 16, withinlet port 28 projecting outwardly as shown through a space 50 in covermember 14. If desired, cover member 14 may be in two pieces, beingseparated at both space 50 and at junction 52, to provide a pair ofgenerally semi-circular cover member sections 53, 55.

Bag or elongated container 20 is inserted into annular channel 16 in aclockwise manner, the length of bag 20 being so proportioned that itterminates adjacent the outlet slot 54 in cover member 14, whichprovides room for the exit of tubing 30. As stated before, pins 34 areplaced through perforations 32 of bag 20 to support the bag in theannular slot 16. Bowl member 12 may typically be adapted to rotate inclockwise manner.

In a first segment 54 of annular slot 16, it will be noted that therepective slot-defining walls of bowl assembly 12 and cover 14 areproportioned to cause the slot to spiral outwardly at an angle 56 ofabout 80 to 85 degrees (specifically 82 1/2degrees which is preferredfor a G field of about 200 to 220 G) from the radius 58 of the circularbowl which intersects the slot at that point. This provides a graduallyincreasing centrifugal force on the blood or other fluid in annularchannel 16 during the centrifugal process as it flows, which causes thered blood cells not only to migrate to the radially-outward wall ofelongated bag 20, but also to migrate in a clockwise manner to the endof spiral section 54 of annular channel 16. The resultant change inradius may preferably be about 0.2 1 cm., specifically about 0.4 cm..Typically, the blood in first segment 54 of slot 16 may be subjected tocontinuously changing G fields as it spirals outwardly by about tenpercent of its radius. Generally, this invention may be used to create Gfields of about 150 to 1,000 g, to obtain the desired separation andcollection of red and white cells at low G fields to avoid theactivation of platelets. The optimum angle 56 will change with differentG fields.

Alternatively, the angle 56 may be 83 degrees, and the G field is about285 G at the blood inlet to slot 16.

At the end of spiral section 54, the annular channel 16 defines aradially-inward step 60. Elongated container 20 is so positioned thatcommunication tubing 44 is positioned at step 60, projecting outwardlythrough aperture 62 in cover 14.

The red cells are retained in the radially-outward pocket defined bystep 60, and may be withdrawn from elongated container 20 through tubing44. Aperture 38 and screen 40 are placed on the radially-outward lateralside of the elongated container, and collect red blood cells with greatefficiency from the pocket defined by step 60.

After the inward step 60, annular channel 16 may define a generallycircular section 64, which terminates in a pocket 66 defined in theannular wall 35 of bowl 12. On centrifugation, elongated container 20tends to distend into pocket 66, to provide a collection reservoir forwhite cells, as well as any red cells that have spilled over from thearea defined by step 60. Communication tube 45 may be positioned on bag20 at this point to withdraw the white cells.

Transverse R.F. seal 39 in elongated container 20 is positioned adjacentinwardly positioned outlet 68, and comprises a pair of upstanding,radially inwardly directed walls 70 and a lateral aperture 72communicating through the annular upstanding wall 74 of cover member 14.

The portion 72 of container 20 which collects platelets is positioned ina section 76 of annular channel 16, which may define a generallycircular arc, containing the downstream end of the container 20 andoutlet tube 30. Generally, upon centrifugation, the platelets gentlyadhere to the outer wall of portion 72 of elongated container 20, andmay be resuspended and stored by agitation within the elongatedcontainer itself in a known manner until ready for use.

It has been found to be generally desirable for section 76 of theannular channel 16 to be positioned radially inwardly from at least thedownstream end of spiral portion 54 of the annular channel, to exert onthe platelets a somewhat lower centrifugal force than that which hasbeen found to be optimum for the collection of blood cells. By thismeans, an optimum centrifugal force (such as 200 to 200 G and preferablyno more than 400 G) for blood cells can be utilized, while at the sametime the platelets do not pack excessively upon the radially outer wallof container 20.

FIG. 7 is a plan view of a variant of the centrifuge bowl of thisinvention. As in the previous embodiment, bowl 80 includes a cover 82which cooperatively defines, with bowl 80, an annular channel 84.Channel 84 may be interrupted by slot 85 in cover 82 to define abeginning portion 86 and an end portion 88. Access tubing 90 and 92 iscarried by an elongated collapsible container 94, similar to bag 20 or20a and positioned within channel 84. Intermediate access tubings 96 and98 are also carried by bag 94.

As in the previous embodiment, portion 100 of the annular channel isoutwardly spirally-shaped for the same purpose as the previousembodiment, terminating in a step portion 102 to provide a pocket forthe entrapment of red cells. Preferably, the same slot configuration isused as in the previous embodiment, to provide the same order of varyingG field. The red cells may then be withdrawn through tubing 96.

Second segment 104 of channel 84 then leads to second step 106, whichmay be larger than the first step 102, and which is for the purpose ofcollecting white cells and any residual red cells that may have escapedthe previous pocket. The white cells may be withdrawn through tubing 98,connecting with container 94.

Third segment 108 of the annular channel 84, containing bag 94, then maydefine a circular arc which is positioned radially inwardly of theentire red cell separating portion 100 of annular channel 84, to reducethe G field for platelet separation by collection on the outer wall ofbag 94, for example a G field of 120 to 125 G.

After cell separation operations are completed, bag 94 is removed, andmay be R.F. sealed to close the bag interior and then severed at area110, for example, for separation of the platelet-containing portion 108of the bag for storage, if desired.

As short separation bag may also be used, turning into and terminatingat slot 111, for the separation only of red cells and plasma. The outlettubing then leads from a radially-inward portion of bowl 80.

FIG. 8 is a perspective view of another bowl in accordance with thisinvention. In this embodiment, no cover is used, but a pair ofelongated, flexible bags 112, 114, of construction generally similar tobag 20 or 20a, are provided in a pair of slots 116, 118 defined in abowl 120.

As in the previous embodiments, a central aperture is defined by sleeve122, provided for fitting upon a centrifuge spindle for rotation.

Inlet tubing 124 is connected to one end of bag 112, being supported byradially inwardly positioned walls 126. In this embodiment, slot 116defines a radially-inward end portion 128, to permit the bag 116 to turnradially inwardly, and then to extend in the circumferential directionthrough the main portion of slot 116.

A first pocket 130 is defined in the outer surface of slot 116, to serveas an initial red cell collecting pocket. Tubing 132 is positioned onbag 112, to be in communication with the bag interior adjacent thepocket 130, to remove collected red cells. Bag 112 and slot 116terminate at second pocket 134, from where tubing 136 (shownschematically) communicates between bag 112 and a conventional bloodpump 138, for example a roller pump for propelling blood through thesystem during centrifugation.

Downstream from roller pump 138, tubing 140, which is an extension oftubing 136, communicates with an end of the second bag 114, residing inslot 118 for collection of platelets in bag 114. The resultingplatelet-poor plasma is then removed from the other end of bag 114through tubing 142.

This arrangement eliminates the need for cutting the bags by providingseparate, elongated, flexible, collapsible bags for blood cellcollection and for the platelets.

White cells will also tend to collect in pocket 134. The entrance oftubing 136 may be positioned only at the top of the bag and at arelatively radially-inward position, if desired, so that the white cellsare retained in pocket 134. Otherwise, other appropriate means forcollection of the white cells, as in the previous embodiments, may beutilized if desired.

Slot 116 may spiral outwardly, if desired, as in the previousembodiments, or may define a circular arc about the axis of rotation.

The above has been offered for illustrative purposes only, and is notintended to limit the invention of this application, which is as definedin the claims below.

That which is claimed is:
 1. A disposable container for use in acentrifuge for separating cellular material, which comprises:anelongated, flat container formed of a flexible plastic material, saidflat container being sufficiently flexible to allow it to be easily bentand inserted into an elongated curvilinear channel defined in acentrifuge for separating cellular material; said container including afluid receptacle portion, a first port communicating with a firstlocation of said fluid receptacle portion for introducing cellularmaterial, and a second port communicating with a second location of saidfluid receptacle portion for extracting a first cellular materialcomponent.
 2. A disposable container as defined in claim 1, in whichsaid container comprises two plies of thin-walled flexible plasticmaterial.
 3. A disposable container as defined in claim 2, in which saidtwo plies comprise a flattened tube.
 4. A disposable container asdefined in claim 1, in which said container includes a third portcommunicating with a third location of said fluid receptacle portion forextracting a second cellular material component.
 5. A disposablecontainer as defined in claim 4, in which said first port is connectedadjacent one end of said fluid receptacle portion, said second port isconnected adjacent the opposite end of said fluid receptacle portion andsaid third port is connected intermediate said first port and saidsecond port connection.
 6. A disposable container as defined in claim 4,includig a fourth port communicating with said fluid receptacle portionfor extracting a third cellular material component.
 7. A disposablecontainer as defined in claim 1, including a portion separated from saidfluid receptacle portion, said separated portion defining means foraiding in connecting said container to a centrifuge.
 8. A disposablecontainer as defined in claim 1, in which said fluid receptacle portionis segmented.
 9. A disposable container as defined in claim 1, in whichsaid fluid receptacle portion has a tapered height between said firstport and said second port.
 10. A disposable container as defined inclaim 1, in which said cellular material is blood.
 11. A disposablecontainer for use in a centrifuge for separating cellular material,which comprises:an elongated, flat container formed of a flexibleplastic material, said flat container being sufficiently flexible toallow it to be easily bent and inserted into an elongated curvilinearchannel defined in a centrifuge for separating cellular material; saidcontainer including a fluid receptacle portion; a first portcommunicating with a first location of said fluid receptacle portion forintroducing cellular material; a second port communicating with a secondlocation of said fluid receptacle portion for extracting a firstcellular material component; a third port communicating with a thirdlocation of said fluid receptacle portion for extracting a secondcellular material component; a fourth port communicating with a fourthlocation of said fluid receptacle portion for extracting a thirdcellular material component; and said first port being connectedadjacent one end of said fluid receptacle portion, said second portbeing connected adjacent the opposite end of said fluid receptacleportion and said third and fourth ports being connected intermediatesaid first port and said second port connections.
 12. A disposablecontainer as defined in claim 11, in which said fluid receptacle portionis segmented and has a tapered height between said first port and saidsecond port.
 13. A disposable container as defined in claim 11, in whichsaid cellular material is blood.